Cataracts are a leading cause of vision loss and health costs. Cataracts occur when there is a build-up of protein in the lens, making it cloudy. This cloudiness in the eye hampers light from passing through the lens.
Some cataracts are related to an inherited genetic predisposition while other causes are related to conditions such as diabetes, trauma or past eye surgery.
Smoking and oxidative stress are also linked to cataracts. As such, researchers are proposing that foods high in antioxidants, especially vitamin C, may help delay the onset of a cataract and also keep them from worsening.
To explore how vitamin C could be linked to cataract formation, researchers looked at over 1,000 pairs of British female twins. Studying twins helps to separate the influences of genetics from environmental factors with genetics likely explaining around one-third of cataract risk and environmental and lifestyle factors the rest.
Out of the lifestyle factors studied, vitamin C consumption was most protective against the risk of developing cataracts. People with the highest intakes of vitamin C from their diet had a one-third lower risk of developing a cataract over 10 years.
Vitamin C also appeared linked to slowing the progression of the disease. The benefit was from food sources of vitamin C; taking a vitamin C supplement did not appear to reduce the risk. The study was observational so it can only show an association between dietary vitamin C and cataract risk.
There is, however, a plausible mechanism explaining the link between vitamin C and cataract progression. The fluid inside the eye contains a lot of vitamin C, which can help prevent oxidation that leads to clouding of the eye lens.
A diet with plenty of vitamin C-rich foods can keep the eye in good supply of this antioxidant nutrient. Foods high in vitamin C include citrus fruits, broccoli and strawberries.
Diet and lifestyle are important factors in cataract development and severity. A well-balanced diet that includes foods with plenty of micronutrient antioxidants such as vitamin C may give the eye a boost in preventing damage.